Develop a portable. rugged device that will measure hematocrit, mean corpuscular volume, and red blood cell count within +-2o% through the use of a novel technique based on measuring the ultrasonic energy back scattered from a blood sample. During Phase I, the proof of concept phase, Key Technologies will assemble laboratory apparatus that mimics the components of the final device and collect data on a population of blood samples. This data will be analyzed to develop detailed correlations which relate the blood parameters of interest to parameters calculated from the ultrasonic backscatter. The accuracy of a device which uses these correlations to calculate hematocrit, mean corpuscular volume, and red blood cell count will be determined based on the accuracy of the correlations and the ability of the device to measure the inputs to these correlations. During Phase II, the product development phase, the experience gained will be used to work with the ultimate customers to develop a prototype handheld device using components that will be found in the final device. Key Technologies will take the correlations developed in Phase I and verify their applicability to the new configuration. The blood sample population will be expanded to include a broad base of patients and pathologies. Once again, Key Technologies will analyze the accuracy and precision of' the system. PROPOSED COMMERCIAL APPLICATIONS: Blood hematocrit is widely used by medical care personnel for diagnostic and monitoring purposes. Existing devices which measure hematocrit are either costly immobile and slow, or inaccurate. The UltraCrit will be accurate, portable, and affordable, giving it a significant advantage over the existing technologies and allowing it to penetrate new markets.